Control device



8- H. A. WHEELER r 2,453,171

CONTROL DEVICE Filed Sept. 26, 1945 4 Sheets-Sheet 1 INVENTOR HwvldA.W/zeeler T'ToRNEYf" Nov. 9, 1948. A, WHE LER 2,453,111

CONTROL DEVICE Filed Sept. 26, 1945 I 4 4 Sheets-Sheet 2 as 42 O INVENTOR HwvldA.W/zeeler Nov. 9, 1948. H. A. WHEELER CONTROL DEVICE Filed Sept. 26, 1945 4 Sheets-Sheet 3 INVENTOR Harold A. VV/zeelez Nbv. 9, 1948.

H. A. WHEELER 2,453,171

CONTROL DEVICE 'Filed Sept. 26. 1945 4 Sheets-Sheet 4 I INVENTOR Harold AM /Leela Patented Nov. 9, 1948 p con'raor. nnvrcr.

Harold Arthur Wheeler, Grand Rapids, Mich., as- 1 signor to Bendix Aviation Corporation, Teterboro, N. .L, a corporation of Delaware Application September 26, 1945, Serial No. 618,742

8 Claims. (Cl. 123-25) The present invention relates to improved control devices andsystems of the class disclosed by application Serial No. 783,237, filed October 31, 1947, by Howard A. Alexanderson as a continuation of application Serial No. 508,724, filed November 2, 1943, and application Serial No. 551,036, filed August 24, 1944, by Howard A. Alexanderson. More specifically, the present invention relates to a novel and improved control mechanism for a supercharged aircraft engine which provides means for effecting automatic control of two intake manifold pressure selection programs for such an engine in response to an operating condition thereof.

An object of the invention is to provide novel means responsive to the intake manifold pressure for adjusting a throttle valve so as to approximate predetermined pressure values together with a single adjustable member for selecting such pressure values and means for selectively actuating said member into operating relation in response to an operating condition.

Another object of the invention is to provide a novel adjustment means for directly actuating an automatic carburetor throttle control in a first sense. and a second novel intake manifold pressure responsive means for directly actuating the throttle control in an opposite sense so as to maintain a predetermined selected pressure value, which value is variable'in accordance with a first selected program, and adjustable means for vary ing such value in accordance with a second selected program.

Another object of the invention is to provide a novel selector linkage arrangement, whereby the datum of the boost control may be selected in accordance with two predetermined programs.

Another object of the invention is to provide a novel control mechanism for selecting in accordance with a first selected program the intake manifold pressure of the aircraft engine, including novel adjustable means for varying the relationship ofthe intake manifold pressure of the aircraft engine in accordance with a second selected program brought into operation by a predetermined operating condition.

During operation of the so-called water or anti-knock fiuid injection systems for suppressing pre-detonation in internal combustion engines, an increase in the air inlet pressure of the induction system for the engine is permissible and desirable'in order that greater engine'power may be obtained than when such injection system is not in operation. Therefore, an object of the invention is to provide a novel regulator responsive to operation of such an injection system for effecting a predetermined increase in the air pressure in the induction system.

Another object of the invention is to provide a novel regulator for effecting smooth control throughout the range of operation of the "antiknock fiuid injection system.

These and other objects of the invention are pointed out in the following description in terms of the embodiment thereof which is shown in the accompanying drawings. It is to be understood, however, that the drawings are for the purpose of illustration only, and are not designed as a definition of the limits of the invention, reference being had to the appended claims for this purpose.

In the drawings:

Figure 1 is a sectional trol mechanism;

Figure 2 is a sectional view taken lines 2--2 of Figure 1; V

Figure 3 is a schematic view showing the control mechanism in operative relation with the aircraft engine controlled thereby;

Figure 4 is a diagrammatic view of the operating mechanism; and

Figure 5 is an enlarged view of the linkage ar-- rangement for the cam follower arm.

The control mechanism as shown in Figures 3 and 4 is preferably operated by a main control lever l pivotally mounted at 2 within the cabin view showing the conalong the of an aircraft. There is pivotally connected to the control lever one end of a main control rod 3.

As shown in Figure 4, there is pivotally connected at the opposite end of the main control rod 3 at I, an arm 5 mounted on a main control shaft 8 and positioned exteriorly of a casing I asshown in Figures 3 and 4. The casing 1 houses the novel control mechanism and may be conveniently mounted on a bracket 'IA as shown in Figures l and 3.

As shown in Figures 3 and 4, there is formed integral with the arm 5, a second arm 8 likewise mounted on the main control shaft 6 and positioned exteriorly of the casing 1. Movement of the arm 8 may be limited as indicated in Figure 3 by a stop 9, which is arranged for engagement by an adjustable limiting screw 8A provided on thearm 8 and a. second engaging arm iii iormed integral with the arm 8.

The main control shaft 6 extends into the casing 1 and is rotatably mounted on suitable antifriction'al roller bearings. not shown.

Positioned within the casing 1 and fixedly mounted at the inner end of the main control shaft 6 is a crank pin II, as best shown in Figures 1 and 4. The crank pin II has pivotally mounted'at the free end thereof a walking beam l2. The walking beam 12 is pivotally connected at one end to a link l3 which is in turn pivotally connected at the other end to an arm ll of a bell crank lever i5, as shown in Figures 1 and 4. The bell crank lever 16 is mounted on a shaft 16.

The shaft i6 is mounted on anti-frictional roller bearings. not shown, and projects through the casing 1, as shown in Figure 4. Mounted at the outer end of the shaft i6 is an arm 11 having pivotally connected at the free end a throttle control rod i8 for adjustably positioning a throttle valve l9 positioned within the air intake conduit of a conventional aircraft internal combustion engine, as indicated diagrammatically in Figure 3.

The throttle valve i9 is arranged so as to regulate the pressure at the intake manifold 20 of an engine 2| by regulating the air inlet through conduit 22 to a supercharger 23. The supercharger 23 is driven by the aircraft engine 21 through a drive shaft 25. The supercharger 23 is arranged to supply air to the intake manifold 20. A canburetor 21 is provided on conduit 22 of conventional type and a conduit 28 leads from the carburetor 21 to a suitable air supply or air intake scoop 29.

Pivotally connected to the arm 8, previously described, is one end of a linkage rod 30. The opposite end of the rod 30 is pivotally connected to one end of a lever arm 3i mounted on a pressureseleetor shaft 32, as shown in Figures 2 and 4. The shaft 32 projects into the casing 1 and 15 preferably mounted "therein on bearing 32A.

The shaft 32 has fixedly mounted at the inner end thereof a cam 33 which may be adjustably positioned by the adjustment of the shaft 32. The cam 33 has provided variable cam surface 34 which is arranged to bear upon a cam follower member 35.

The cam follower member 35 projects from the lower end of a lever 36 pivotally supported intermediate its opposite ends by a pin 31 carried by an arm 38. As shown in Figures 2 and 5, the arm 38 is pivotally mounted at the lower end on a pivot pin 39 which projects through a suitable opening 40 formed in the lever 36. The pivot pin 39 is eccentricaliy affixed to an adjustment screw 4i carried by the casing 1.

A tension spring 42 is coiled about the pin 39 and has one end 43 held securely by a portion 64.

of the casing 1. The other end 45 of the spring 42 bears upon the lower end of the lever 36 and tends to bias the lever 36 in a counter-clockwise direction about the pivot pin 31 carried by the arm 36 and the member 35 into contacting relation with the cam surface 34.

The upper end 46 of the arm 38 is operably engaged by one end of a rod 41 for shifting the position of the pivot pin 31 of the lever 36 for a purpose which will be explained hereinafter.

It will be seen from the foregoing arrangement that upon inward adjustment of the rod 41 to the left, there will be imparted a counter-clockwise movement to the arm 36 about the pin 39 which will cause in turn the pivot pin 31 for the lever 36 to shift in a counter-clockwise direction about the fixed pivot 39. Movement of the pivot pin 31 causes the lever 36 to likewise shift in a counter-clockwise direction about its cam engaging member 35 against the biasing force of the spring 42. The opening 46 permits movement clockwise direction about the fixed pivot 39. Thus the arm 39 under force of the spring 42 moves in a clockwise direction about the fixed piv0t'39 and follows the movement of the rod 41 to the right. The opening 46 permits the return movement of the lever 36 under the biasing force of the spring 42 as the pivot pin 31 is shifted in a clockwise direction about the fixed pivot 39 during the latter operation of the rod 41.

The upper end of the lever 36 is moreover pivotally connected to one end of a floating lever 50. The floating lever 59 is pivotally connected at an end 5|, to one end of a linkage arm 62. The linkage arm 52 is operatively connected at the opposite end to a pressure responsive mechanism indicated generally by the num beral 53 which will be hereinafter described.

Servo-motor mechanism A third link 54' is pivotally connected to the floating lever 56 at a point intermediate the opposite ends of the lever 56. The opposite end of the link 54 is afiixed to a slidably adjustable member 56 for controlling a servo-valve of conventional type. As shown in Figure 1, the member 56 is slidably mounted within a valve sleeve- 56A positioned within the wall of the casing I. Carried by the servo-valve control 56 is a tension spring 51 which exerts a force biasing the link 54 toward the floating lever 56. ,The valve sleeve 56A has provided ports 56. 59. 60, 6| and 62, as shown in Figures 1 and 4. The ports 59 and Si are connected by suitable conduits 63 and 64, respectively, to a servo-motor indicated generally by the numeral 65, while a conduit 66 is connected to the port 60 and serves as an inlet to the servo-valve of, a suitable fiuid medium under pressure such as oil under engine pressure for operation of the servo-motor 65. A drain conduit 61 is further connected to the ports 56 and 62 and serves as an outlet for the fluid pressure medium supplied to the servo-valve in the conventional manner.

As shown in Figures 1 and 4, a servo-piston 68 is slidably mounted within a cylinder wall 69 of the servo-motor 65. The piston 68 is connected to a piston rod 16 in any conventional manner. A tension spring 1| .biases the piston 68 in a direction tending to slide the rod 16 outwardly from the cylinder 69 for a purpose which will be explained hereinafter. Movement of the piston 68 in response to the biasing force of the spring 1i is'limited by a collar 12 against which the piston 68 abuts in the extreme biased position.

As shown in Figure 1, suitable telescoping tubular members 13 and 16 are provided for protecting the spring 1| and limiting the extent of movement of the piston 66 in the opposite direction.

The conduits 68 and 64, previously described, lead to opposite sides of the piston 68 so that adjustment of the servo-valve control 66 to the left of the neutral position shown in Figure 6, will; cause the conduit 63 to serve as an inlet of pressure to the servo-motor 65 and thereby exert a V BEST HVAELABLE COPY biasing force upon the piston 88 to the right. Likewise, adjustment or the servo-valve control 80 to the right of the neutral position shown in Figure 6,-will cause the conduit 54 to serve as an inlet of pressure to the servo-motor 58 and exert biasing force upon the piston 88 to the left. Thus it willbe seen that in the conventional manner the direction of movement of the piston .the piston rod H3 under control of the power means-aforesaid, is pivotally connected by a link 75 to the opposite end of the walking beam I: from thatat which the link is is connected, as

7 previously described. It will thus be seen that the adjustment of the walking beam i2, and accordingly the throttle control shaft i8 is dependent upon the effect thereon of the adjustment of the main control shaft 6 and the servo-motor 85.

The adjustment of the servo-motor 85 is dereadily sub-.

light isnsiouspring 31 mounted on the member. a

Thus it will be seen that in normal operation a decrease in the intake manifold pressure due to a rise in altitude for example, decrease in atmospheric pressure or other cause, would affect the bellows 16 and 11 so as to cause the relative contraction of the bellows l6 and the relative expension of the bellows 17. Such action would cause the movement of the plate I2 and the longitudinal movement of the linkage arm 32 toward the left, as viewed in Figures 1 and 4.

Since, as previously explained, the spring 42 exerts a greater biasing force than the spring 51, it will be readily seen that such longitudinal movement of the arm I! would cause the floating lever 50 .to pivot in a clockwise direction on its pivotally connection to the arm 86 resulting in a corresponding longitudinal movementof the link pendent upon the adjustment of the pressure se- Pressure responsive mechanism The pressure responsive mechanism 5 3, previously noted, comprises preferably a pair of bellows 1B and 11 mounted within the'casingl, as

- best shown in Figure 1, The bellows His preferably partially evacuated and balanced by a coil spring" mounted within the bellows 11 so as to act against the biasing force of the bellows 16. A wall 18' formed within thecasing 1 has mounted thereon the bellows 16 which is connected through a passage 80 passing through the wall 18, and a conduit 8i connecting the passage 80 to the intake manifold 20 of the internal combustlonaircraft engine 2|, as shown in Figures 1/3 and 4, in such a' manner that the biasing force of the bellows 16 will vary in response to the intake manifold pressure. A plate 82 is mounted between the bellows 16 and TI and is movable upon variance in the pressure exerted within the bellows I6, as'is well known in the art.

The plate '82 has provided a projecting arm 83 to which there is pivotally connected an end of the linkage arm 52 previously described. The opposite end of the bellows i1 is mounted on a plate sion exerted by the spring 42 and acting upon the arm 38 has a considerably'greater'biasing force upon the servo control valve member 56 5t and servo control valve member 58 to the left.

Thus with the control valve member 68 first in the neutral position, such adjustment of the servo control valve member 55 would cause the opening of the port 59 to the inlet of the pressure medium provided through the port 60 resulting in the shifting of the piston 68 to the right 'as viewed in Figures 1 and 4 and the mechanicaladjustment of the throttle I! to a relative increased open position through the action of the piston rod 10 on the link 15, walking beam'iZ, link [3, bell crank lever i5, throttle control shaft 15, arml1, and rod i8, and thereby increasing the pressure exerted at the intake manifold 20.

Conversely, an increase in the intake manifold pressure would cause the relative expansion of the bellows l6 and contraction of the bellows ll, resulting in the longitudinal movement of the linkage arm 52 to the right.

Obviously, since the movement of the lever arm 36 would be prevented by the'spring 42, the latter adjustment of the linkage arm 52 would cause the counter-clockwise movement of the floating lever 50 about its pivotal connection to the arm- 35, causing a corresponding longitudinal movement or the servo control valve member 56 to the right.

Thus with the control valve member first in the neutral position, such adjustment of the servo control valve member 56 would cause the opening of the port 6i to the inlet of the pressure medium provided through the port 69 causing a shifting of the piston 68 and the mechanical adjustment of the throttle 19 to a relative decreased open position and thereby decreasing'pressure exerted at the intake manifold 20.

Thus it will be seen that there is provided automatic means for compensating for either an increase or decrease in the pressure at the intake manifold 20, so that a predetermined standard pressure condition may be approximated. Obviously, upon standard pressure conditions being approximated, the pressure responsive mechanism 53 will cause the adjustment of the servo control valve member 56 to a neutral position.

It will be further seen that there has been provided adjustment means whereby the value of the predetermined standard pressure condition may be varied, Thus upon movement of the control lever i, as shown in Figure 4, in a counterclockwise direction, a clockwise movement of the main control shaft 6 will result, causing a corresponding clockwise movement of the walking beam i2 about its pivotal connection to the link 15 and causing in turn the clockwise movement of the throttle control shaft I 6 so as to move the throttle than the force exerted thereon by the relatively ii to a relative open position.

Furthermore, It will be seen that such adjustment of the control arm I will cause also the clockwise movement of the arm 8 and a corresponding clockwise rotation of the cam 33, as viewed in Figure 4, for changing the datum or setting of the pressure responsive mechanism 53.

Pressure selection mechanism It will be noted that as the lever member I of Figure 4 is moved in a counter-clockwise direction, the pressure setting of the bellows 53 is increased by causing the lever 35 to be adjusted in a counterclockwise direction about the pivot 31. Thus the highest pressure setting is obtained at the lowest rise of the cam surface 34, while the lowest pressure setting results at the highest cam rise.

Further, upon adjustment of the rod 41 to the left, the pivot 31 is shifted in a counter-clockwise direction about the pivot 39 so as to effect a second higher pressure setting program.

This latter higher pressure setting program is likewise adjusted through the operation of the cam 33 under the control of the lever I.

Water injection system As best shown schematically in Figure 3, there is connected to the carburetor 21 a conduit I leading from a suitable source of fluid fuel for the aircraft engine. There is also provided a conduit IOI for injecting the fuel into the induction system through a nozzle I02. There is further provided a conduit I03 for injecting into the induction system through nozzle I02 a supplemental or socalled anti-knock fluid medium such as water, water-alcohol or other suitable fluid well known in the art for suppressing predetonation of the eng The conduit I03 is connected to a suitable metering device shown in dotted outline and indicated generally by the numeral I04. The latter metering device may be of suitable type well known in the art for determining the rate of flow of the supplemental" fluid, and, since the herein invention resides in the regulator means rather than in the metering device, the same has been shown diagrammatically by the outline indicated by numeral I04.

A conduit I leads to the metering device I04 from a suitable source of supplemental" fluid indicated by numeral I08. In the conduit I05, there is provided a pump indicated by numeral I01 driven by a suitable power means not shown. The pump I01 supplies the fluid medium under pressure to the metering device I04. A valve I08 is provided In the conduit I30 between the pump and the metering device I 04 for "oil" and on" control of the supplemental" fluid injection system. The control valve I00 may be of any suitable type, but is shown herein as of an electromagnet controlled type having an electrical control circuit I09 and switch IIO which is preferably mounted within the aircraft cabin for convenient operation by the pilot. Thus the supplemental fluid injection system may be placed in operation by the pilot closing the switch IIO so as to effect the opening of the valve I00. Conversely. the valve I08 may be closed by opening the switch IIO. A by-pass conduit III and relief valve H2 is provided for recirculating the fluid medium from the pump outlet to the pump inlet at such times as the'valve I00 is closed and the Injection system is not in operation.

A conduit H3 is connected to the conduit I05 between the valve I00 and the metering device I04. The conduit II3 leads to a control mecha- 8 nism II4 arranged so that during operation of the injection system, the rod 41 is shifted to the left by the pressure of the supplemental fluid medium acting under force of the pump 25. as will be explained hereinafter. It will be readily seen that when the injection system is in operation the fluid medium will exert through the conduit H3 a greater pressure under force of the pump I06 than when the injection system is not in operation.

Control mechanism responsive to operation of waterjnjection system The control mechanism indicated generally by the numeral II4 includes as shown in Figure 1, a plug or casting I I5 which projects into the casing 1 and has slidably mounted therein the rod 41. Formed in the outer end of the casting H5 is a recessed chamber I I6 open through a port I I1 to atmosphere or other reference pressure.

Extending across the chamber H1 is a diaphragm I I8 which is fastened in position between the outer end of the casting IIS and a casting H9 by bolts I20.

Formed in the casting II9is a chamber I2I sitioned at the opposite side of the diaphragm II 0 from the chamber I I6. The conduit II3 opens into the chamber I2I so as to subject the diaphragm I I8 to supplemental fluid injection pressure when the latter system is in operation.

A spring I22 is provided at the opposite side of the diaphragm and normally biases the diaphragm I I8 to the right when the water injection system is not in operation.

The rod 41 which bears at one end upon the arm 30 has its opposite end fastened to the diaphragm H0 by the fastening screw I23. There is also secured at the opposite side of the diaphragm II8 by the screw I23 an arm I24 which is arranged to engage a member I25 so as to limit the movement of the diaphragm IIB to the left.

The member I25 is aiiixed to an adjustable screw I26 screw threadedly engaged in a nut I21 rotatably mounted in the casing H0. The screw I20 is restrained from rotary movement relative to the casting I I9 by a pin I28 which projects into the chamber I2I and engages the member I20.

The nut I 21 is thus so arranged that convenient adjustment of the member I25 may be readily effected so as to determine the limit of movement of the rod 41 to the left under the biasing force of the supplemental fluid injection pressure.

A flange I29 is provided on the rod 41 so as to limit the return movement of the rod 41 to the right under force of the spring I22 upon the cessation of operation of the supplemental fluid injection system. The flange I29 engages a washer I 30 mounted at the inner end of the casting or plug H5 and held in position by a suitable snap ring I 3| It will be readily seen from the foregoing that upon operation of the supplemental fluid injection system there is effected an increase in the fluid pressure exerted in the chamber I2I, The diaphragm IIO under such increased pressure actuates the rod 41 so as to effect an adjustment of the arm 38 in a counter-clockwise direction shifting the pivot pin 31 and the lever 38. Thus there is effected an increase in the pressure setting of the bellows 53 for a given position of the control lever I during operation of the supplemental fluid injection system. The extent of such increase in pressure setting may of course. be conveniently varied through appropriate adjustment of the nut I21. Likewise the pressure returned under 'force o fdthespring I22 to the normal position and the arm 46 is biased under force of spring 42 to the position shown as previously explained.

Lock out limiting means There is further provided means to lock out the automatic means, whereby upon adjustment of'the main control lever I, to apredetermined minimum standard pressure selection position, the opening of the throttle I9 may be affected only'by the manual adjustment ofthe control lever 1 without regard to the pressure existing at the intake manifold or the condition of the pressure responsive mechanism. This is specifically accomplished by providingan adjustable abutment rod I33 best shown in Figures 1 and 4 and explained in detail in the copending application of Howard A. Alexanderson, Serial No. 508.724, filed November 2, 1943. The abutment rod I35 is screw'threadedly engaged in the wall I9 and projects through the wall I8 into the bellows I6. A suitable cleft. I36 is provided in the abutment 1'odI35 and is positioned exteriorly' oi the bellows 16 so that the abutment rod I35 may be conveniently adjusted longitudinally for calibration purposes. The abutment rod I35 .is arranged so as to engage the plate 82 upon the pressure in the intake manifold decreasing to a predetermined low value equal to the critical standard value at which the automatic control for opening-the throttle is to be discontinued and manual control alone remains.

"A second abutment rod I3! is also mounted within 'the bellows H as shown in Figure 1, for the purpose of limiting the excessive expansion of bellows l6 and contraction oi bellows TI which might otherwise cause mechanical damage thereto. I

There is further provided a third safety means for preventing the automatic opening of the throttle I9 past a predetermined maximum critical point, and the said safety means so arranged that such opening of the throttle past 10 actuating stop pin I46 slidably mounted within a sleeve member. The stop pin I45 projects through the sleeve into the valve sleeve 56A where it is adapted to engage in its inward position, the free end of the servo control valve rod 58. The pin I48 is normally biased by a spring I46 into a disengaging relation from the rod 56. Inthe latter position the pin I45 under the biasing force of the spring I46 actuates the arm I33 in a counter-clockwise direction against a stop pin I41 mounted in the wall 1. Upon the throttle I9 being opened to..a predetermined point the bell-crank'lever I5 will be positioned so as to cause the knocker arm I38 to engage the'roller I43 mounted on the arm I39. Continued clockwise adiustment of the bell crank lever I5 will cause arm I39'to actuate the pin I45 inward so as to prevent control valve rod 56 from being adjusted through the lever I50 to a position to the left of the neutral position. In the latter locked position a decrease in pressure at the intake manifold 20 would cause merely a contraction of the bellows I6 and the actuation of the lever 50 so as to cause the movement of the lever 36 in a counter-clockwise direction against the biasing force of the spring 42. Further clockwise movement of the bell crank lever I5 will cause the pin I45 to actuate thevalve rod 56 to'the right of the neutral position and the piston 63 to such point, 'mayonly-be accomplished under the positive manual control of the lever I.

This function is specifically accomplished by providing the bell crank lever I4, previously described, with a knocker arm I38 arranged for actuating the arm I39. The arm I39,-as shown in Figures 1' and 4, is pivotally mounted at one end on an eccentric pin I40 carried by an adjustment screw I4I.', The adjustment screw MI is screw threadedly engaged in the wall of the casing I. The positi n of the arm I39 in relation to the knocker arm I 38 may be conveniently adjiisted for calibration purposes by'means of the screw I4I which extends throughthe wall of the easto the exterior; as shown and described in detail in the copending application of Howard A. Alexanderson Serial No. 783,237, flied October 31, 1947," as a continuation'of application Serial No. 5b8,'i2'4',"filed November 2, 1943, and now aban- "ea-rammin arm I39 is a pin I42, on which is' mounted aroller I43arranged for engagement b'y'tli knocker arm I38 as shown in Figures 1 and 45" There further projects from the arm I39 a member I44 which'is arranged to engage a valve the extreme left hand position shown, whereupon, further opening of the throttle valve I3 may bedirectly effected-by manual operation of lever I.

' Operation cam 33 positioned by the pilot operated control lever I.

Moreover, upon operation of the water or supplemental fluid injection system, the cam follower arm 36 is automatically efiected so as to provide a higher pressure setting program than when the system is not in operation. V

The apparatus may bearranged so that during the operation of the high pressure setting program, the low pressure lock out I35 will'not be brought into operation due to the high pressure setting provided. However, during operation of thelow pressure setting program the latter lock out I35 may become effective when the lever I has been adjusted to within a minimum pressure setting range.

Similarly during the operation of the low pressure setting program, it will be readily seen that within a limited low altitude range the lock out I45 will not become effective due to the relative low selected pressure. The lock out I45 in the latter altitude range will become efiective during the operation of the high pressure setting program when the control lever I has been adjusted to within .a maximum pressure setting range. The lock out N5 may also become efiective dur lug-operation of either the high or low pressure setting programs at excessively high altitudes or within extremely low atmospheric pressure regions as the throttle I9 is adjusted to extreme open positions to meet the pressure setting.

Although only'one embodiment of the invention has been illustrated and described. various changes in the form and relative arrangements of the parts, which will now appear to those skilled in the art, may be made without departing from the scope of the invention. Reference is,

1 1 therefore, to be had to the appended claims for a definition of the limits of the invention.

What is claimed is: 1. A regulator for the induction system of a supercharged aircraft engine, comprising, in combination, a boost control for regulating said induction system so as to maintain the pressure thereof at a predetermined value. acam, a lever connected to said boost control for changing the datum thereof and operably positioned by said cam, a member pivotaliy mounting said lever. an arm carrying said first mentioned pivot member, a second member pivotaliy supporting said arm, a spring carried by said second member and biasing said lever about said first mentioned pivot member into contacting relation with said cam, said arm being arranged to shift said first mentioned pivot member against the biasing force of said spring so as to change the pressure selected by said cam.

2. In a boost control, the combination comprising a cam, a cam follower lever operably connected to said boost control for varying the datum thereof, a first member for pivotally supporting said lever, an arm carrying said first member. a second member for pivotaliy supporting said arm. a spring coiled about said second member and biasing said lever into contacting relation with said cam, and said arm being arranged so as to effect adjustment of said first member from a first to a second position against the biasing force of said spring so as to change the datum of said boost control. I

3. In a boost control, the combination comprising a" cam, a cam follower lever operably connected to said boost control for varying the datum thereof, a first member for pivotaliy supporting said lever, an arm carrying said first member, a

second member for pivotaliy supporting said arm.

a spring coiled about said second member and biasing said lever into contacting relation with said cam, said arm being arranged so as to effect adjustment of said first member from a first to a second position against the biasing force of said spring so as to change the datum of said boost control, a rod for actuating said arm, a diaphragm afllxed to said rod, a spring biasing said rod in one direction and said diaphragm responsive to fluid pressure for actuation ofthe rod in an opposite direction.

4. In an aircraft internal combustion engine of the type including a carburetor for supplying a combustible mixture to said engine, operable means for injecting a supplemental fluid for suppressing predetonation of said engine, a supercharger for supplying air to the induction system of said engine, a throttle valve for controlling the induction pressure, and a boost control for regulating the throttle valve: the improvement comprising means for changing the datum of said boost control, a pilots control lever operably connected to said datum changing means, means responsive to operation of said supplemental fluid injection means for actuating said datum changing means from a first to a second datum changing program, means limiting the adjustment of said throttle valve by said boost control. and means connecting said lever and throttle valve so as to effect manual control of said throttle valve within said limited range.

5. In an aircraft internal combustion engine of the type including a carburetor for supplying a combustible mixture to said engine. operable means for injecting a supplemental fluid for suppressing predetonatlon of said engine, a supercharger for supplying air to the induction system of said engine, a. throttle valve for controlling the induction pressure, and a boost control for regulating the throttle valve; the improvement comprising means for changing the datum of said boost control, a pilots control lever operably connected to said datum changing means, means responsive to operation of said supplemental fluid injection means for actuating said datum changing means from a first to a second datum changing program. means limiting the adjustment of said throttle valve by said boost control within a predetermined range of adjustment of said lever during the non-operation of said supplemental fluid injection means, and other means limiting the adjustment of said throttle valve by said boost control within a, predetermined range during operation of said supplemental fiuid injection means, and means connecting said lever and throttle valve for manual control of the throttle valve within said limited ranges.

6. In an aircraft internal combustion engine,

control member to said automatic means, a fluid pressure sensitive membrane connected to said connecting means so as to shift the pressure setting range of said first mentioned automatic means from a first to a second predetermined program, and means operably connecting said membrane to the supplemental fluid injecting means so as to cause an increase in said pressure setting in response to operation of the supplemental fluid injecting means.

7. In an aircraft internal combustion engine, the combination comprising operable means for injecting a supplemental fluid for suppressing predetonation of said engine, a boost control for regulating engine induction pressure so as to maintain the pressure thereof at a predetermined value, a cam, a pilot's control member to adjust the cam, a lever connected to said boost control for changing the datum thereof and operably positioned by said cam, a member pivotaliy mounting said lever, means for shifting said pivot member from a first to a second position so as to change the datum changing program of said boost control from a first to a second predetermined program, a fluid pressure sensitive membrane operably connected between said last mentioned means and said fluid injecting means to cause the shifting of the pivot member upon operation of said supplemental fluid injecting means.

8. In an aircraft internal combustion engine. the combination comprising operable means for injecting a supplemental fluid for suppressing predetonation of said engine, a boost control for regulating engine induction pressure so as to maintain the pressure thereof at a predetermined vaiue, a cam, a pilots control member to adjust the cam, a lever connected to said boost control for changing the datum thereof and operably positioned by said cam, a member pivotaliy mounting said lever, means for shifting said pivot member from a first to a second position so as to change the datum changing program of said boost control from a first to a second predetermined program, and a. spring biasing said lever into conm tasting relation with said cam and opposing- 3 ENCES CITED movement of said pivot member from said first to Th f w n r ferenc s are of record in the said seeond'position, said pivot shifting means fi Of this P inciudinfl a fluid pressure sensitive membrane for 5 actuating said pivot member from the first to IE: STATES PATENTS the second. position, and means operabiy con- Number Name i Date necting the membrane to said fluid injecting 2,031,527 Dodson Feb. 18, 1936 means. 7 317,364 Haliord et a1 ..Oct. 8, 1940 HAROLD ARTHUR WHEELER. 10 2,392,565 Anderson et a] Jan. 8, 1946 

